Detachable bit rock drill



Patentecl Sept. 30, 1941 DETCHABLE BIT ROCK DRLL Gusta.ve Knutson, SouthPorcupine, Ontario, Canada, assignor, by mesne assignments, to

International Detachable Bits & Equipment, Limited, Timniins, Ontario,Canada, a corporation of Ontario, Canada Applieation March 31, 1938,SerialN0. 199,200

Claims.

My invention relates to improvements in detachable bit rock dril1sparticularly of the type wherein the connecton between bit and shankcomprses a dovetail tongue on one member inseitable into a dovetail slotin the other member, and. an object of the invention is to devise enimproved form of dovetail connection between bt andshank which will tendto 1etain the bit in axia1 aiignmeht vvith the shank during drilling endobviate the liability of its being deflected rom its course due to siipsand other changes in rock formation.

A- furtherobject of the inventon is the previsin of means on thedovetail tongue engageable with an abutment in the dovetail slot forfurther assisting in keeping the bit in axia1 algnment with the shank asit can only be detached from such shank trom theside from which it hasbeen inserted.

With the above and other objects in view which will hereinafter appearas the specification proceeds my invention, in ts preferred embodment,consists of the construction en as hereinafter more particularlydescrbed and illustreited in the mccompanying drawing in which:

is applied to the shank in axial alignment and the dri1l nserted into ahole in the rock which may have been previously begun by a starter dri11or other dri1l, the axes of bit and shank Wil1 remain substantiallycoincident as the bit cannot s1ide sidewise relatively to the shankunless its axis is disposed angularly to the shank. Such augu- 1arity isobvously prevented by the wa1l of the hole being drilled.

Referring to the specific construction of my invention as illustrated inthe drawing, the shank l provided with the usual axia1 Water orfice 2therethrough has a. cupped bt engaging end 3 with a dmetrical slot 4 ofdovetail cross-section extending thereacross.

longitudinal verticai section conforming with the Fig. 1 is a. side viewof a, rock dril1 constructed according to my invention.

Fig. 2 is a. similar view taken at right angles to Fig. 1.

Fig. 3 is a side view (partly in secton) showing the detachable bitpartially inserted into or detache-d from the shank.

Fg. 4 is a vertical section of the shank taken on the line 4-4 (Fig. 5).

Fig. 5 is a, plan view of the snank, end Fgs6 and 7 are side views ofthe detachable bit teken at right ang1es to each other.

Like characters of reference indicate correspondng parts in thedifferent views of the drawng. 1 l -I1XO it has been the practice indovetail connections betweer bit and snacnk to have the dovetail slotand dovetail tongue extend straight across shank -zmd bit respectivelyat substantilly right angles to their axes. 'Ihe disadvantage of suchconstruction is that the dovetai1 tongue, bing lateraliy movable in thedovetail slot, tends to permit the bit to get out of axial algnment Withthe shank during drilling and to be deflected frem ts course.

According to my invention, I obviate this disadvantage by making thedovetail tongue substantially arcuate in longitudinal vertica1 sectionand the dovetail slot a1so correspondingly arcuate curvature of theeupped end 3. Arcua.te grooves 5 and 6 are provided respectively in eachside wa11 of the slot 4 in the vicinity of its arcuate roof and suchgrooves areopposedly positioned in the side wa11s of the slot so as toextend fromtheir ends to substantialiy emid-point in their 1ength. Thedetachable bit provded with cutters 8 and an axia1 water orifice 9 has adomed upper portion l0 corresponding to the cupped end 3 of the shankinto which it is adapted to be received and a diametrically extendingtongue U of dovetail cross-section corresponding to that of the dovetailslot 4 inthe shank surmounts the domed upper portion II) of the bit,such tongue being arcuate in iongitudinal vertical section correspondingwith the curvature of the slot 4 in the shank. A- projection 12 isprovided en e sidewall of the tongue II at its mid-point and isreceivable into a groove 5 or 0 in the wa1ls of the slot 4 when the bitis applied to the shank.

In appiying the bit to the shank, its axis is dsposed at an angle to theaxs of the shank as illustrated in Fig. 3 and the end of the tongue IIis inserted into the slot 4. Simultaneously the projection 12 isinserted into the groeve 5 or 6 depending from which side of the shankthe tongne is introduced. Then by sliding the bt laterally, the tongueII foliows the slot 4 until the axis of the bit becoms coincident withthe axis of the shank. In such postion the projection I2 abuts aganstthe end Of the groove 5 or 6 and further movement of the hit in suchdirection is prevented. The bit. can now only be moved in a reversedirection to the direction in which it has been inserted in the shank.

The cupped end 3 of the shank I abuts the domed portion 10 of the bitand consequently a, rigid detachable connection between bit and.

in the same secton. Consequently, when the bit shank is consttuted.

Such slot is arcuate in From the above desoription t will be apparentthat I have devised a detachable bt drill in which the dovetailconnecton between bit and shank is suchthat in drillng, lateral movementof the former relatively to the latter is obviated by the provision ofthe arcuate tongue and arcuate slot assisted by the projection on thetongue abuttng the end of a groove in one sde wa1l of the arcuate slot.

Although I have illustrated and described the arcuate tongue as being onthe bit and the arcuate slot in the end of the shank these elements may,if desired, be reversed. l

What I claim as my invention is:

1. In a detachable bit rock drill, the combination with a shank memberand detachable bit member, of a detachable connection between bit andshank members comprising a. diametrical tongue of dovetail cross-sectionand arcuate in longitudinal vertical seotion on the end of one of themembers receivable into a correspondingly shaped slot in the end of theother member.

2. In a. detachable bit rock dril1, the combination with a shank memberand detachabie bt member, of a detachable connection betweenbit andShank members comprising a diameizrical tongue of dovetail cross-sectionand arcuate in longitudinal vertical secton on the end of one of themembers receivable into a. correspondngly V shaped slot in the end ofthe other member, and

coaoting means between tongue and slot for preventing the tongue beinginserted into the slot further than a postion in which the axes of bitand shank are coincident.

3. In a detachable bit rock drill, the combinaton wth a shank member anddetachable bit member, of a detachable conhection between bit and shankmembers Comprising a, diametrical tongue of dovetailcross-section andarcuate in longitudinal vertical section on the end of one of themembers receivable into a correspondingly shaped slot in the end of theother member, and a projection on a side wall of the tongue insertab1einto an arcuate groeve in a side wall of the slot, said grooveterminating at a mid-poimt in the length of the slot.

4. A detachabie bit rock dri1l comprising a shank havng a diametricalslot of dovetail crosssection in its bit engaging end, said slot beingarcuate in longitudinal vertical seetion, and a detachable Dit having adiametrcal tongue of dovetail cross-section on its shank engaging end,said tongue being arcuate in longtudinal vertcal section correspndng tothe curvature of the slot into which it is inserted.

5. A detaichable bit rock dri1l comprising a shank having a) diametrcalslot of dovetal crosssection inits bit engaging end, said slot being.arcuate in 1ongitudinal vertcal section, and a detachable bit having adametrical tongue of dovetail cross-section on its shank engaging end,said tween bit and shank for preventing the insertion of the tongue intothe slot past a position in which the axes of bit and shank arecoincident.

6. A detachable bit rock dri1l comprisng a shank having a dametricalslot of dovetail crosssection in its bit engaging end, saidslot beingarcuate in longitudinal vertical section, a detachab1e bit having adiametrical tongue of dovetal cross-secton on its shank engaging end,said ongue beng arcuate in longitudinal vertical secton corresponding tothe curvature of the slot into which it is inserted, and 2, projecton ona side WaQ1l of the tongue insertable in an arcuate 'groove in a. sidewa11 of the slot, said groove terminating at a mid-point in the lengthof the slot.

dmetrical slot of arcuate cross-section in such tongue being arcuate inlongitudinal vertical section corresponding to the curvature of the slotinto which it is inserted, and coactingmeans beend, said slot bengarcuate in longitudinal vertica.l section, 2. 'detachable bit; having adomed portion receivable into the cupped end of the shank, and adiametrcal tongue of dovetail cross-section and arcuate in longitudinalvertica.l section corresponding to the curvature of the slot in theshank int0 whch t is receivable, and coacting mans between bit and shankfor preventing the insertion of the tongue into the slot past a positionin which the axes of bit and shank are coincident. 9. A detachable bitrock drill comprising a shank witha cupped bit engaging end and adiametrical slot of arcua te cross-section. in such end, said slot beingarcuate in longitudinal vertica1 secton, adetachable bit h aving a.domed portion recevable into the cupped end of the shank, a diametricaltongue of dovetail crosssection and arcuate in longitudinal verticalsection correspondng to the curvature of the slot in the shank intowhich it is receivable, and a, projection en a side wall of the tongueinsertabl in an arcuate groove in a Sde Wa11 of the slot, said grooveterminatng at a. mid-point in the length of the slot.

10. In a rock-drlng combination, a shank member havng a concave endportion curved on a radius having a center on the axs of said shank andprovided with a diametric dovetail slot curved on a radius havng acenter coinciding wigh said first named center, and a bit member havingan end portion and.diametric dovetail portion curved complementally to,and adapted to engage, respectively, sad curved shank end and dovetailslot.

GUSTAVE KNUTSON.

